StyleResolver should update RuleSets lazily.

Source/core/css/RuleSet.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 13 matching lines @@
 
 #include "core/css/RuleFeature.h"
 #include "core/css/StyleRule.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/LinkedStack.h"
 
 namespace WebCore {
 
 enum AddRuleFlags {
-    RuleHasNoSpecialState         = 0,
-    RuleHasDocumentSecurityOrigin = 1,
-    RuleCanUseFastCheckSelector   = 1 << 1,
-    RuleIsInRegionRule            = 1 << 2,
+    RuleHasNoSpecialState            = 0,
+    RuleHasDocumentSecurityOrigin    = 1,
+    RuleCanUseFastCheckSelector      = 1 << 1,
+    RuleIsInRegionRule               = 1 << 2,
+    RuleSkipsFontFaceAndViewportRule = 1 << 3

[eseidel, 2013/11/06 01:39:10]

Does this mean you can have rules which ignore the fact that they're defined
inside an @font-face or @viewport?  I must be misunderstanding, as that doesn't
make sense to me...

[tasak, 2013/11/06 05:42:26]

I mean, if RuleSkipsFontFaceAndViewportRule is set, we will ignore @font-face
and @viewport in a given stylesheet.

Because the rules have been already processed in
filterFontFaceAndViewportRulesFromAuthorStyleSheets (invoked from
lazyAppendAuthorStyleSheets).

I'm using the flag to avoid invoking "addViewportRule" or "addFontFaceRule" from
appendPendingAuthorStyleSheets.

 };
 
 enum PropertyWhitelistType {
     PropertyWhitelistNone   = 0,
     PropertyWhitelistRegion,
     PropertyWhitelistCue
 };
 
 class CSSSelector;
 class ContainerNode;
@@ skipping 53 matching lines @@
     unsigned d[4];
 };
 
 COMPILE_ASSERT(sizeof(RuleData) == sizeof(SameSizeAsRuleData), RuleData_should_stay_small);
 
 class RuleSet {
     WTF_MAKE_NONCOPYABLE(RuleSet); WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<RuleSet> create() { return adoptPtr(new RuleSet); }
 
-    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, StyleResolver* = 0, const ContainerNode* = 0);
+    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, StyleResolver* = 0, const ContainerNode* = 0, bool processFontFaceAndViewportRule = true);
     void addStyleRule(StyleRule*, AddRuleFlags);
     void addRule(StyleRule*, unsigned selectorIndex, AddRuleFlags);
+    void addViewportRule(StyleRuleViewport*);
 
     const RuleFeatureSet& features() const { return m_features; }
 
     const RuleData* idRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
     const RuleData* classRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
     const RuleData* tagRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
     const RuleData* shadowPseudoElementRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }
     const Vector<RuleData>* linkPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_linkPseudoClassRules; }
     const Vector<RuleData>* cuePseudoRules() const { ASSERT(!m_pendingRules); return &m_cuePseudoRules; }
     const Vector<RuleData>* focusPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_focusPseudoClassRules; }
@@ skipping 24 matching lines @@
     typedef HashMap<StringImpl*, OwnPtr<LinkedStack<RuleData> > > PendingRuleMap;
     typedef HashMap<StringImpl*, OwnPtr<RuleData> > CompactRuleMap;
 
     RuleSet()
         : m_ruleCount(0)
     {
     }
 
     void addToRuleSet(StringImpl* key, PendingRuleMap&, const RuleData&);
     void addPageRule(StyleRulePage*);
-    void addViewportRule(StyleRuleViewport*);
     void addRegionRule(StyleRuleRegion*, bool hasDocumentSecurityOrigin, const ContainerNode* scope);
 
     void addChildRules(const Vector<RefPtr<StyleRuleBase> >&, const MediaQueryEvaluator& medium, StyleResolver*, const ContainerNode* scope, bool hasDocumentSecurityOrigin, AddRuleFlags);
     bool findBestRuleSetAndAdd(const CSSSelector*, RuleData&);
 
     void compactRules();
     static void compactPendingRules(PendingRuleMap&, CompactRuleMap&);
 
     struct PendingRuleMaps {
         PendingRuleMap idRules;
@@ skipping 21 matching lines @@
     Vector<StyleRulePage*> m_pageRules;
     Vector<StyleRuleViewport*> m_viewportRules;
 
     unsigned m_ruleCount;
     OwnPtr<PendingRuleMaps> m_pendingRules;
 };
 
 } // namespace WebCore
 
 #endif // RuleSet_h